Proportional divider



Sept. 30, 1958 w. MORGAN 2,853,784

PROPORTIONAL DIVIDER Filed Nov. 9, 1956 INVENTOR lVTljlfor an V nZZW United States Patent This invention relates to a proportional divider and has for its primary object to provide such an instrument which can be utilized for accomplishing the same functions and results as the proportional divider disclosed in my prior U. S. Patent No. 2,301,068, issued November 3, 1942, and which present instrument due to an improved construction is capable of-being constructed of fewer parts without a .loss of function resulting from omission of parts.

A further object of the invention is to provide an improved proportional divider which may be utilized for accomplishing additional functions for which the instrument of my prior patent could not be employed.

Still a further object of the invention is to provide a proportional divider of extremely simple construction which may be very economically manufactured and sold, yet which may be efiiciently and accurately'utilized for accomplishing the numerous functions for which it is intended.

More specifically, it is an object of the present invention to provide a proportional divider including a pivoted arm carried by a slide, which arm and a straight longitudinal edge of a base, on which the slide is mounted, intersect at the center of the pivot axis of the arm.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawing, illustrating a presently preferred embodiment thereof, and wherein:

Figure 1 is a fragmentary top plan View of the proportional divider;

Figure 2 is a fragmentary cross sectional view thereof, taken substantially along a plane as indicated by the line 2-2 of Figure 1;

Figure 3 is a fragmentary longitudinal sectional view,

taken substantially along a plane as indicated by the line 3-3 of Figure 1, and

Figure 4 is an enlarged fragmentary horizontal sectional view, taken substantially along a plane as indicated by the line 44 of Figure 2.

Referring more specifically to the drawing, the proportional divider in its entirety is designated generally 6 and includes an elongated base, designated generally 7, herein disclosed as comprising a relatively thick bar 8 and an elongated thin plate or strip 9 which is suitably secured to the bottom side of the bar 8. The plate or strip 9 may be formed of steel or other suitable material and extends from end-to-end of the bar 8 and is preferably of a width greater than the width of said bar so that the plate 9 has longitudinal side edge portions 10 and 10 extending outwardly from the side walls 11 and 11 of the bar 8 and which have outer longitudinal edges, disposed parallel to said side walls 11 and 11', which are designated 12 and 12. The upper surface of the bar 8, designated 13, is provided with a groove 13' extending from end-to-end thereof, which is of inverted T-shape cross section and which is preferably disposed midway between the side walls 11 and 11. Said upper "ice surface 13 and the upper surfaces of the side edge portions 10 and 10 may be provided with a plurality of longitudinal rows of graduations forming various linear scales 14.

A slide, designated generally 15, includes a bar 16 of a cross sectional shape to slidably engage the groove 13', as best seen in Figure 2, and a plate 17 which-is secured at a point spaced from its ends to the upper side of the slide bar 16 by fastening's 18. The plate 17 is preferably formed of a rigid transparent material-and is disposed with its longitudinal axis crosswise of the base 7 and slide bar 16, and has an index line or hairline-19 extending longitudinally thereof and which is thus dis posed crosswise of the base 7, and which maybe employed with the graduations of any one of the scales 14.

One end portion 20 of the slide plate 17 extends outwardly to substantially beyond the side wall 11 and to beyond the side edge 12, which is located therebeyond and parallel thereto. A screw 21 extends upwardly through an opening 22 in the plate portion 20, as best seen in Figure 2, and is turnably and slidably disposed therein. An elongated arm 23 has an enlarged inner end 24 which is provided with a central opening 25. The opening 25 is shaped to receive the beveled head 26 of the screw 21 therein, so that the underside of the head will be disposed flush with the flat underside of the arm 23 including its end 24. A thumb nut 27 threadedly engages the upper portion of the screw 21 and bears against the upper side of the plate portion 20, and a spacer sleeve 28 is mounted on the screw 21, between the arm end 24 and the underside of the plate portion 20. A portion of said end 24 and the screw head 26 will bear against a portion of the upper side of said side edge portion 10.

The arm 23 has an inner straight edge 29, an extension of an inner end of which will intersect the longitudinal center of the screw 21, which constitutes the pivot axis of said arm 23, as best illustrated in Figure 4. Further, the longitudinal edge 12 of the base 7 also intersects the axis of the screw 21, so that said screw axis is disposed at the intersection of the edges 12 and 29 which constitute two rule edges of the proportional divider 6. The upper surface of the arm 23 along its inner edge 29 may be provided with scale markings 30. The arm 23 is of a width no greater than the width of the side edge portion 10 so that said arm may be swung clockwise to an inoperative position overlying the side edge portion 10 when the instrument 6 is not in use, and as illustrated in dotted lines in Figure 1.

The edges 12 and 29 thus form an angle having the axis 21 as an apex and which is formed by true edges, whereas in my aforementioned prior patent the hinge axis of the swingable arm was offset outwardly from an adjacent side edge of the base. Thus, the edges 12 and 29 may constitute two sides of a triangle with a line inscribed on a surface on which the instrument 6 is disposed and by positioning one of the graduations of the scale 14, which is inscribed on the side edge portion 10, at one end of the line forming the other side of the triangle and then moving the slide 15 toward said graduation at intervals corresponding to the spacing between the graduations of said scale while using the edge 29 to mark the line forming the third side of the triangle, at each different position of the slide 15, said third side of the triangle can be accurately divided into any desired number of equal parts.

It will also be readily apparent that the edges 12 and 29 may be positioned relative to one another to form an angle of any desired. size and after which said edges may be utilized as rule edges for scribing the angle on any surface against which the instrument 6 may be applied. The slight spacing of the arm 23 from any sur- Patented Sept. 30, 1958- 3 face on which the instrument 6 is disposed, representing the thickness of the strip 9, will be insufficient to adversely affect the use of the arm 23 as a ruler. It will also be understood that the thumb nut 27 may be tightened to secure the arm 23 immovable relative to the slide 15 so-that the: edge 29 thereof will form a desired angle With the base edge 12. It will further be noted that the hairline or index line 19 may be utilized with various ones of the several linear scales 14, and in addition the longitudinal edges of the plate, 17,, which are disposed parallel to the hairline 19, maybe utilized as index lines in conjunction with the several scales 14.

The slide 15can be removedfrom the bar 8 and the slide. bar 16 reversed and re-"applied to the groove 13' for positioning the inner end 240i the arm and the arm pivot 21over the side edge portion 10 of the base 7 and so that the: arm-edge 29 can then function with the base edge 12'. When thus' disposed, the index line or lines of the slide may be most conveniently utilized with the linear scales 14 disposed on the side portion 10' and on the upper surface of the bar 13 adjacent its side wall- 11..

It. will also be apparent that various other forms of slides may be substituted for the slide 15 and still main tain the relationship between either the side edge portion 10 or 10 and the arm 23 and its pivot 21. Likewise, the instrument 6 may be made in various sizes and various other modifications and changes are contemplated and may be resorted to, without departing from the function or. scope of the invention as hereinafter defined by the appended claim.

I- claim as my invention:

An instrument of the character described comprising an elongated base including a thick bar and a thin rigid plate secured to a bottom surface of the bar and having an edge portion extending outwardly from one side of said bar, said edge portion having a straight outer edge disposed parallel to the longitudinal axis of the bar and to said side thereof, said bar having a groove extending from end-to-end thereof of inverted T-shape cross section and opening outwardly of an upper side of the bar, a slide including a member fitting slidably in said groove and a rigidtransparent strip secured to the upper surface of said slide member and extending across. the upper side i of said bar, one end of said strip projecting laterally from the upper side of the bar and overlying said edge portion of the plate, pivot means supported by and depending from said laterally projecting end of the transparent strip and disposed in a plane perpendicular to the plane of the plate, said pivot means comprising a headed screw extending upwardly through said end of the transparent strip, a nut engaging the upper end of the screw above said strip, and a sleeve mounted on the screw and disposed between the screw head and the: underside of the strip, an. arm having an enlarged apertured head at one end thereof through which the screw extends, said apertured head being disposed between the screw head and a lower end of the sleeve for supporting the arm in a plane parallel to the plane of said plate above and adjacent the level thereof for swinging movement in the plane of said arm about said pivot means as an axis, said arm having a straight edge intersecting the straight edge of said plate at the axis of said pivot means, said arm being of a width corresponding to the width of said edge portion of the plate to assume a folded inoperative position overlying apart of said edge portion of the plate and with the straight edge of the arm in alignment with said straight outer, edge. of the plate, the upper side of said bar and said side edge portion of the plate being provided with linear scales, and said transparent strip having an index line disposed crosswise of the base and intersecting the axis of said' pivot means for use with said linear scales, said nut being manually turnable for clamping the apertured head between the screw head and sleeve for holding the arm immovable relative to the slide for retaining the straight edge of the arm at a desired angle relative to said straight outer edge of the plate or in alignment with the straight outer edge of the plate.

References Cited in the file of this patent UNITED STATES PATENTS 

